Cotton coats tend to tangle easier than silky coats, but that doesn't mean silky coats can't tangle. You may be dealing with puppy coat. Individual yorkies develop their coats at different rates. Max's was gone very early, whereas Teddy's coat took almost 2 years to become fully silky.
Grooming when your pup is tired is a very good plan. Keep working with him every day to accept grooming. I find it easier to put the dog on a counter, and I body block the dog and I am always prepared to stop any attempt to jump. Safety first! Make grooming a positive experience: talk to him, praise him. Be patient and confident. If you are anxious, he will sense that and really want to get away. Keep coaxing him to stand in place and allow you to work.
I know what you mean about 3 hands, maybe 4 hands. That would be nice! I have learned how to use my hand to hold the section of hair and steady the dog a bit while I use the other to comb or brush.
To reach those difficult spots takes a little practice. For the chest and armpits, I have my guys sit and I do as much from the front as possible. Then I have them stand and I get the back of the armpits and the undercarriage.
I have found that the best defense against tangles is to keep my boys as clean as possible and to use a good conditioner. When there is a tangle to be undone, I like to use the tail of a rat tail comb first (Mimimomo, Jenny, sells the Madan comb at her site toplinepet.com) to carefully break it up and follow up with a comb that has medium and then closely set teeth.
If the tangles are really bad, I would recommend shaving or cutting them off and starting over (be very careful with scissors, work in bright light, and put your fingers between the scissors and skin to avoid a cut).
Finding a good groomer is a difficult quest. That is why I do all of my grooming at home myself.
Hope this helps.
